Abstract
In this case, oral prednisolone (PSL) treatment was initiated for immunoglobulin M nephropathy in a 7-year-old female patient; however, proteinuria increased. Urine protein to creatinine ratio prior to treatment was 1.1 g/gCr, but worsened to a maximum of 4.3 g/gCr. Serum albumin levels were also decreased and subsequently, the PSL dose was tapered. After 8 weeks of treatment, PSL was judged ineffective, and was discontinued. Following PSL discontinuation, urine protein levels quickly recovered to the pretreatment value. So it was diagnosed as drug-induced injury caused by PSL. In a drug-induced lymphocyte stimulation test, the result for Predonine® tablet was positive while the result for Medrol® tablet was negative. With hydroxypropyl cellulose (HPC), an additive present in Predonine® tablet only, the result was positive; therefore, HPC was judged as the causal substance. Thus, this case suggests that steroid drug-induced kidney injury must be considered if urinary protein level increases prior to treatment discontinuation, and additives should be evaluated even during the selection of other drugs. Notably, HPC was the causal substance here; thus, it is an additive for which caution is required.
